Several methods have been used to provide selectable outputs on a high power transmitter. All use a switch circuit or device to select the output. Mechanical switches are limited by reliability and speed. PIN diode switches add significant loss and weight. Ferrite switches add loss, weight and driver complexity.
Signal distribution networks such as Butler matrices are well known in the art, and examples are described, e.g. in U.S. Pat. No. 3,255,450, which describes a binary network matrix, and U.S. Pat. No. 4,638,317, which describes a matrix with a non-binary set of outputs.